How to fix iPhone 16 Pro Max camera and photo-saving issues?

Brand new 512GB iPhone 16 Pro Max. Up-to-date iOS. Restarted and reset many times daily to try to get the camera to work, it did work for a while yesterday, finally! Now it’s back to not working. It’s also a crapshoot whether I will be able to save a photo (from Facebook or the internet), take a screenshot, or access my old photos to send or post them. Most of the time I can’t. Photos freezes and crashes. I can take photos using the camera within iMessage, Facebook messenger, or instagram messenger, but once again cant save them 80% of the time.

Seems like this is a common problem with the current iOS? How to fix it?

[Re-Titled by Moderator]